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IMPORTANCE An intraoperative higher level of positive end-expiratory positive pressure (PEEP) with alveolar recruitment maneuvers improves respiratory function in obese patients undergoing surgery, but the effect on clinical outcomes is uncertain. OBJECTIVE To determine whether a higher level of PEEP with alveolar recruitment maneuvers decreases postoperative pulmonary complications in obese patients undergoing surgery compared with a lower level of PEEP. DESIGN, SETTING, AND PARTICIPANTS Randomized clinical trial of 2013 adults with body mass indices of 35 or greater and substantial risk for postoperative pulmonary complications who were undergoing noncardiac, nonneurological surgery under general anesthesia. The trial was conducted at 77 sites in 23 countries from July 2014-February 2018; final follow-up: May 2018. INTERVENTIONS Patients were randomized to the high level of PEEP group (n = 989), consisting of a PEEP level of 12 cm H 2 O with alveolar recruitment maneuvers (a stepwise increase of tidal volume and eventually PEEP) or to the low level of PEEP group (n = 987), consisting of a PEEP level of 4 cm H 2 O. All patients received volume-controlled ventilation with a tidal volume of 7 mL/kg of predicted body weight. MAIN OUTCOMES AND MEASURES The primary outcome was a composite of pulmonary complications within the first 5 postoperative days, including respiratory failure, acute respiratory distress syndrome, bronchospasm, new pulmonary infiltrates, pulmonary infection, aspiration pneumonitis, pleural effusion, atelectasis, cardiopulmonary edema, and pneumothorax. Among the 9 prespecified secondary outcomes, 3 were intraoperative complications, including hypoxemia (oxygen desaturation with SpO 2 Յ92% for >1 minute). RESULTS Among 2013 adults who were randomized, 1976 (98.2%) completed the trial (mean age, 48.8 years; 1381 [69.9%] women; 1778 [90.1%] underwent abdominal operations). In the intention-to-treat analysis, the primary outcome occurred in 211 of 989 patients (21.3%) in the high level of PEEP group compared with 233 of 987 patients (23.6%) in the low level of PEEP group (difference, −2.3% [95% CI, −5.9% to 1.4%]; risk ratio, 0.93 [95% CI, 0.83 to 1.04]; P = .23). Among the 9 prespecified secondary outcomes, 6 were not significantly different between the high and low level of PEEP groups, and 3 were significantly different, including fewer patients with hypoxemia (5.0% in the high level of PEEP group vs 13.6% in the low level of PEEP group; difference, −8.6% [95% CI, −11.1% to 6.1%]; P < .001). CONCLUSIONS AND RELEVANCE Among obese patients undergoing surgery under general anesthesia, an intraoperative mechanical ventilation strategy with a higher level of PEEP and alveolar recruitment maneuvers, compared with a strategy with a lower level of PEEP, did not reduce postoperative pulmonary complications.

We evaluated the effect of epinephrine on the duration of analgesia of 20 mL ropivacaine 0.5% or 0.2% injected in femoral three-in-one block for pain relief after total knee replacement. Our results show that epinephrine does not alter the duration of analgesia of the two solutions investigated.

Background: A role of bacterial superantigens in several chronic inflammatory diseases has previously been proposed. Many of these diseases are associated with an imbalance of the T helper cell subsets and their cytokine production. Methods: Peripheral blood mononuclear cells from healthy donors were incubated with various concentrations of staphylococcal enterotoxin B (SEB) with or without IL-4 or IFN-γ. After different time points cell activation, proliferation, Fas expression, cytokine release and cell death via apoptosis were detected. Results: SEB treatment resulted in sequential T cell activation, proliferation, Fas expression, cytokine release, subsequently followed by cell death via apoptosis in a dose- and time-dependent manner. This biphasic effect occurred preferentially in SEB-responsive cells represented by the expression of Vβ3 and Vβ12 on T cells. A strong relationship between T cell activation and apoptosis was observed. The amplitude between these events increased with the dose of SEB. The highest rate of apoptotic T cells was observed at a dose of 1,000 ng/ml SEB. Addition of IFN-γ to SEB-treated cells significantly reduced the rate of apoptotic cells, whereas IL-4 prevented apoptosis only in SEB-untreated cells. Conclusion: These results support the concept that the dose of superantigen exposure determines the rate of T cell proliferation and subsequent cell death. This T cell immune response is modulated by the presence and the type of cytokines.

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These findings indicate an influence of cerebrospinal fluid density on subarachnoid distribution of 3 ml plain bupivacaine 0.5% and show that with higher cerebrospinal fluid densities, a higher spinal block level can be expected.

P Pu ur rp po os se e: : This dose-response study was designed to determine the most appropriate dose of ropivacaine 0.5% injected via an indwelling femoral catheter for perioperative peripheral analgesia for total knee replacement (TKR).M Me et th ho od ds s: : 84 patients were allocated randomly to four groups and received, via a femoral catheter, either 15, 20, 25 or 30 mL of ropivacaine 0.5% in a double-blind fashion. An anterior sciatic block with 20 mL bupivacaine 0.5% was also performed. The evolution of sensory block of femoral, obturator and lateral femoral cutaneous nerves and motor block of femoral nerve were tested every five minutes during the first 30 min. The percentage of patients with complete sensory block of both femoral and obturator nerves determined success rate. General anesthesia was then induced. After surgery, patient-controlled analgesia (PCA) with ropivacaine 0.2% was available via the femoral catheter. The interval between the initial injection and the first PCA administration determined duration of action.R Re es su ul lt ts s: : The duration of action was not different between the four solutions tested i.e., 534 ± 379 min for 15 mL, 799 ± 364 min for 20 mL, 624 ± 342 min for 25 mL and 644 ± 266 min for 30 mL. The percentage of patients with complete sensory femoral and obturator blocks was, respectively, 60%, 95%, 85% and 70% for 15, 20, 25 and 30 mL (P = 0.008/15 mL vs 20 mL).C Co on nc cl lu us si io on n: : Although there is no difference in duration of analgesia, because of better sensory spread, 20 mL of ropivacaine 0.5% appears to be the most appropriate dose for peripheral analgesia after TKR. 60 %, 95 %, 85 % et 70 % pour les doses de 15, 20, 25 et 30 mL (P = 0,008/15 mL vs20 mL Objectif